12 replies to this topic

[Pine]

I have an argument with a friend: I said traction control only reduces engine power when it’s more than the rear tires can handle, and he said it also uses the brakes to regain traction and can also add more power when the driver lifts too sharply and there's danger of oversteer due to weight transfer.

Who is right and who is wrong?

Thanks,
Pine

[Ali_G]

Pine: Generally TC cuts power from the engine to stop wheel spin. The general way to do this is to stop maybe 2 cylenders frm firing to reduce HP. I beleive this is what Williams and tohers did in the early 90's.

But there is also the option of just having the computer cut the revs. But of course for this to work the car would have to be Drive by Wire. But today it doesn't matter as all cars have this feature.

In a true TC the car should have its brakes linked to a CPU. But I beleive that the new FIA rules will not allow this. They make mention to the braking systems and also ABS is still banned.

Niall

[Top Fuel F1]

Pine:

Only have time for one more short Post today. Anyway also consider the electronically conrolled torque dividing differential apportioning torque for various traction situations.

Mean while there is a mass of discussion about TC on the BB already. Try some Searches on: traction, TC, salisbury, differentials, etc. It will speed things up if you limit the Search to the Technical Forum.

Best Regards;

[Ali_G]

Ya I remember that McLaren were using a very technical (contraversial) Split Differential Device which ran on Electronics.

The idea is that to aid turning one of the rear wheels should reduce its torque to aid the steering. Its in every car even road cars. But the problem is that this system can take away power from a wheel that is slipping. So its a sort of TC.

Niall

[PDA]

Many road car amti yaw systems act by braking one side at the front or back, depending on whether it is controlling over or understeer. The current F1 rules do not allow braking to be assymetrical, so brake activated systems will not be allowed unless the rules are changed. Expect TC systems to work by reducing engine power when wheelspin is detected.

[Ali_G]

As I remember Braking can be contraversial. McLaren had a pedal in 98 which only operated the rear brakes. Seemingly it was useful for stopping oversteer while in a corner. But that was later banned.

Niall

[desmo]

Niall, the McLaren "fiddle brake" was a device whereby the driver manually selected the side which he was turning to, and used the fiddle brake to alter the effective torque split, effectively helping to steer the car into or out of the corner.

May I suggest that you read a few basic texts on how cars work, virtually every post you make contains massive errors, which is fine we all must start somewhere. However, you seem more or less uninterested in taking the time to learn the fundamentals of how a car works. May I also respectfully ask that rather than posting assertions that must be corrected by others, when you have read up on the basics of the operation of cars, use this forum which has a great depth of knowledge to answer the questions which naturally arise as you are learning the fundamentals. I think everyone here would be happy to help get you up to speed, but do your part and put in some time learning the basics first. This stuff is widely available on the web or at your local library for free. If you have trouble finding sources of information I and I expect others will be happy to be of assistance.

I would like much this forum to be accessable to those who aren't fluent in the techspeak of automobiles, but at the same time I'd like to be able to assume that the posters and readers here have a very basic understanding of the workings of an automobile so we aren't constantly diverted off topic explaining things that even the most casual of automobile enthusiasts take as a given.

If anyone disagrees with this, please feel free to chime in with your opinions.

[Pine]

Wow! I ask a question, come back after 11 hours, and I have 6 replies and a new issue of Atlas F1 that half of it is dedicated to the exact question I asked. Excellent.

Much less excellent was seeing that according to Williams Shoebotham’s article I was wrong -- big time! However, I tend to think PDA is right and the brakes will not be used in next year’s TC systems. I certainly hope so.

Thank you all for your replies,
Pine

[Ali_G]

Desmo: I am only recalling this from a thing I saw on TV.

Question: How can one pedal affect the torque which goes to either of the rear wheels.

Niall

[desmo]

Ali, the driver actually selected the direction of the upcoming turn and the second brake pedal actually only applied the brake on the side of the inside of the turn. This was outlawed by the FIA by the rule that said that asymetric braking from side to side was disallowed. This is a good example of how innovation is stifled by over-regulation as the idea was almost certainly legal at the time of it's introduction. McLaren's subsequent lack of vigor in defending the concept has lead some to conclude that either the idea was of limited real use or that they had developed a differential that would impart the desired turning moment.

[Ali_G]

Desmo: Sorry. I heard Martin Brundle saying that it was a device which let the drive use the rear brakes only.

But here was the bit I could not understand. That he could then brake deeper into the corner without understeer. But I really couldn't understand this as this would cause more oversteer.

Niall

[Top Fuel F1]

Has everyone read the article "Comprehensive Traction Control in F1" on the Atlasf1 Home Page? I've printed it out for an easier read. Maybe those who have specialized in the thinking on this subject could comment (+ or -) on it's content. One thing I have already thought about is that one of the 2000 problems may still exist in 2001; but this time for a different reason. As it was, the teams with the most resources could have possibly created psuedo TC, when the r teams with less had not/could not. Now that TC would be legal the teams with more resources would be developing the premium TC, where the teams with less may only be able to implement the bargain basement versions. I believe TC will not be an "out of the box" kit.

[PDA]

Ali - the "fiddle brake" does only act on the rear brakes. In fact, it acts only on one rear brake. The driver selected which side on entering the corner by flicking a switch on the steering wheel. The fact that this nmade it a "manual" system was the basis for Macs argument for it to be legal. The fiddle brake is used not on entry, but when the power is put back on. The tendency is for the inside rear wheel to spin, becasue it is less loaded than the outside wheel (especially in slow corners, where downforce in minimal, by applying the brake to the inside wheel, it is prevented from spinning. Mac reckomed that as this was manually controlled, it was a legal, limited, traction control system. Also, slowing that wheel causes excess torque to be transferred to the outside wheel, where it will do most good. So, reducing torque on the inside, and increasing torque on the outside, effectively produces a turning moment on the car, reducing understeer on exit. Ferrari and co protested on the basis that the primary function of the system was to steer the car, i.e. rear wheel steering. Rear wheel steering is not allowed in F1, and the stewards agreed with Ferrari's argument (in spite of the fact that the system had been considered legal by Charlie Whiting, the FIA technical consultant. The fact that Mac did not appeal leads me to think that they maybe had an electronic diff in development which would achieve the same effect. the Kerfuffle before Monza this year when Ferrari asked for a "clarification" of the diff rules may be indicative of this (but by no means definative). BTW, such a torque biasing diff, electronically controlled is not that difficult to design, Honda e.g. have such a system on hteir "R" rated cars and the S2000.